class Gem::RemoteFetcher

def fetch_path(uri, mtime = nil, head = false)
  uri = URI.parse uri unless URI::Generic === uri
  raise ArgumentError, "bad uri: #{uri}" unless uri
  unless uri.scheme
    raise ArgumentError, "uri scheme is invalid: #{uri.scheme.inspect}"
  end
  data = send "fetch_#{uri.scheme}", uri, mtime, head
  if data and !head and uri.to_s =~ /\.gz$/
    begin
      data = Gem.gunzip data
    rescue Zlib::GzipFile::Error
      raise FetchError.new("server did not return a valid file", uri.to_s)
    end
  end
  data
rescue FetchError
  raise
rescue Timeout::Error
  raise UnknownHostError.new('timed out', uri.to_s)
rescue IOError, SocketError, SystemCallError => e
  if e.message =~ /getaddrinfo/
    raise UnknownHostError.new('no such name', uri.to_s)
  else
    raise FetchError.new("#{e.class}: #{e}", uri.to_s)
  end
end